Electrically conductive stripe applicator



May 20, 1952 J. KALLl-:NBORN ELECTRICALLY CONDUCTIVE STRIPE APPLICATOR 4 Sheets-Sheet 1 Filed Jan. 10, 1947 May zo, 1952 J. KLLENBRN ELECTRICALLY coNDUcTIvE STRIPE APPLICATOR 4 Shets-Shee 2 Filgd Jan. 1o, 1947 May 20, 1952 J. KALLEN'BQRN ELECTRICALLY CONDUCTIVE STRIPE APPLICATOR 4 Sheets-Sheet 3 Filed Jan. l0, 1947 May201952 y J. KALLENBORN 2,597,106

ELECTRICALLY CONDUCTIV STRIPE APPLICATOR Filed Jan. 1o, v194'? 4 sheets-sheet 4 Patented May 20, 1 952 Unirse PATENT' orties 2159110@ ELECTRICALLSE GLoNDUoClJIvE s'ritIrE-l ABPLICATOR .lohn Kanenbornf, Perf-Allegany, raz, assigner t'o' leittslnirghl Cu'riiig'f Corporation; Allegheny?lv County',;Pa;, arcprporation1- of vPen/ns'ylyania- Application Januaryjll), 1947;w SerialNo. "ZJZ` 3) Claims.'

The* present invention' relates to" proc'esse's ofv and" apparatus' forl applying 1 stripes to sheets of glassi and-'it has particular relation to' such proc'- es sjan'd`- apparatus as may4 hev employed' toapply stripesl of" electrically conductive material con# tiguous to the edges Yof sheetspfglass'; themargins of which are` to` loe'V heated electrically; bent and Welded' to a'seco'nd sheet in order to' form adouble glazedunit'. s Y

One objectof" the"v invention to provide'a" double glazedunits whichcan" be "substitutedf'or" conventional single plates 'K or panes of glassV in" windows byjheating to thesoftening p'oint'and thenhendingfover theedgesof one pane'or'plate of"gl`ass and sealing asecond p'aneorE plate there# to byjrfusing; orv sintering `the Acontacting portions to provide-y a iseale'd monolithic unit. Such units` arecharacterized'bythe permanent exclusion ol." moisture-'fromth'e interior thereof'.v Also the" air or `othe'1""^ga's sealed* therein provides an excellent non-conductive-medium for heat which consti-'- tutesthe unitf and` excellentl heat` insulator; An" excellent processeoffand apparatus forV construct# patent 101D. E. Gray'2,398,525.f` In-the-lpatented processthe-heating of the' edges of the glasstis* efectedhy localized electrical' conductance. In orderf to initiate Vthe electrical' heating operation it{isldesirable'to applya-'stripe of anl electricallyconductive=material such" as aquadag* (a water;

suspension ofgraphite-) nearff to' but` slightlyf spaced from'I the` margins of `thel glas'sf sheets.

After;theheating"'operation has been adequately? initiated theglass l, itself 'constitutes ac'onductor an'dfheating can b'eso continued even afterftheaquadag: film .haslb een burned i away.'

Inforderto obtain. uniform bending 'and Weld-i ingfo'fthe heated 'portions of" glass, .itis essentialthat fthey conductive stripes! of aquadag be 1 uni# form in thickness and Widthso as to obtain uniform; conductivity about the: entire f perimeter of eachf sheet 1- oiL-L glass. stripes have been` applied' by vpassingi the 1 glass betweentheiconvention'alrollersi-aetingfmuclathe1 (cl. 11a- 122191 sameas' ringer rollersorlnipper rollers However.' bylmea'ns of' such` crude apparatus it'y has? heenA dii'licult orimpossible toobtain the accurate spac-v in'gjof'the stripes and-uniformity'as'to thickness and' Width of the" coatings so essential-to satis-J factory performance of the subsequent Welding steps:

Inaccordance withthe' provisions-ofthe pres-vr entA invention, it is proposed toobviate the fore#Y l:going difculties in the striping ofl glass-sheetsto be'fwelded together b y carrying fthe sheets uponV a conveyor havingA guide anges maintaining thel sheetsac'curately positionedvvith respect tol the striping apparatus. As a further feature the invention contemplates the provision eis-a striping device ofY rollers engaging' the lower'face ofitheglass near two opposite edges, therollers being resiliently supported so thatV they followv theirregularities -in the surface" of the glass-and furtheri being driven insucheman'nerasf'toY oppose the' movement of? Vthe glass sheetsy beingstriped. As a still further feature the invention'i echtem# platesprovisionof two longitudinally spaced sets of striping devices and means betweenformfe'- chanically and' accurately rotating or in'decing a'slie'eto'f gl'as'sV striped ino'n'e directionby one;

set ofi devicesv through aA desiredA angle 'and then feeding? it" to .the second striping "mechanism for? striping-in another dr'cto rFor' a betterV understanding! of 'the' invention,

reference maynoW behadf tothe accompanying? provisionsiof thepresent invention; i

Fig; 4 is; a fragmentary sectionalV` view .taken substantially upon'the lines''fIV-IV of` Eiglij Fig; 5 is y'a1fragfnenta'ry'detail viewof the drive! and :4;

Figs'lla andfb vareiviews of vlafvplate offglassff showing: certain stages involvedr inlits treatments The'- ap'parat'us as shown' in Lthev drawings; two" unitsWa'ndS, `W being fany convenient emloo'dif--r mentofapparatus designed preliminaril-y to'fwash' the@ g-lassandincludinga :shell 1 designedtof pre;v

y in bearings vent splashing of wash liquids. Conveyor rollers 'Ia driven by flexible connection such as a belt or chain 1b carry the glass plates through the washer. A chain or belt trained about a gear 1c on one of the shafts is also driven by a suitable motor and speed reducing mechanism 1d.

Unit S is the striping mechanism proper and comprises a framework designated broadly at 8 with side rails 9, lower platform 9a and upright supports Ill. The apparatus S may be considered as comprising sections A, B and C.

Section A constitutes a loading and preheating section or reachI section B comprises a striping and indexing mechanism adapted to apply stripes slightly spaced from all four margins of a plate of glass and section C comprises a section or reach for drying the stripes upon glass plates and for unloading the glass from the system. Sections A and C include conveyor rollers II journaled at their extremities in bearings I2 shown in Fig. 1. The rollers are provided contiguous to the side rails with axially adjustable guide flanges I3 preferably approximately of frusto conical axial section and having shoulders I4 upon whichthe plates of glass (G) are adapted to ride so that the plates are supported by their extreme edges, leaving the surfaces to be striped free of contact and obviating any tendency to smear the stripes before they are dried. Mechanism for driving the conveyor rollers II includes a sp-rocket chain I5 engaging sprocket gears I6 upon the extremities of the rollers Below the rollers in section A, are disposed preheaters such as electrical heaters including reflectors I1 and heating coils I8 disposed thereabove designed to preheat lthe glass before the stripes are applied thereto.

Section C is substantially similar to the section A and also includes the rollers I I, journaled I2 and similarly driven by the sprocket chain I5. Heater elements 22 below the conveyor rollers are designed to heat the glass upon the rollers for purposes of drying the aquadag stripes.

Appropriate mechanism for driving the conveyor system includes a motor 23 upon the platform Sa and having a drive shaft 24 to which is secured a pulley or sprocket gear 26 having a flexible driving element such y as a V belt or sprocket chain 21 trained thereabout. The drive element 21 also engages gear or pulley 28 upon a shaft 25 of a speed reducing mechanism 3l of conventional design. This mechanism is provided with a power take-olf shaft 32 having an appropriately driving connection 33 with a conveyor roller indicated for purposes of distinction as IIa. The latter, in turn drives thesprocket I6a and chain or belt I5.

Mechanisms indicated broadly in Figs. 1, 2 and Bas 34 and 35 for applying stripes slightly spaced from the edges of the plates of glass are longitudinally spaced with respect to each other and are of duplicate construction. Therefore, description of one is believed to be sufficient for both. The mechanisms include transverse rollers 36 journaled in bearings 31 shown in dotted line in Fig. 2 as being disposed below the rails 9. Each of these rollers is provided with a sprocket gear or a V belt pulley 38, shown in Fig. 3 about which is trained a flexible connection, e. g., a sprocket chain or a V belt 39 further trained about a sprocket or pulley 40 upon one shaft or roller distinguished as I Ib of the conveyor system. The shaft or roller 36 is further provided with a pickup roller 4I keyed or otherwise appropriately fixed upon the shaft and dipping into a suitable trough or container 42 for the striping material such as a suspension of graphite in water conventionally known as aquadag. The trough may be supported in any convenient manner, e. g., by brackets 42a (Fig. 3) on frame 8.

Applicator mechanism for picking up aquadag from the roller 4I and applying it as a uniform strip to the surface of a plate of glass G includes a disc or roller 43 of appropriate width, keyed upon a stub shaft 44, which in turn is journaled in a frame or housing element 45. These elelments 45 as shown in Fig. 4 include ends 46 of rectangular outline and have an opening 41 formed therein in which opening a bearing block 48 upon the shaft 36 is slidably disposed. These blocks 48 are adjustable in the slot 41 by means of set screws 49 and 5I threaded in the element 46 and bearing at their extremities upon the lower and upper surface of the block 48. In order to admit of access to the set screws 5 I, an opening 52 is formed in the element 46 above the opening 41 into which opening the upper extremities of the screws 5I project. Nutsv 53 and 54 upon the set screws constitute means for locking said screws in any desired position of adjustment. It will be apparent that by appropriately adjusting the screws 49 and 5I position of the applicator disc 43 may be varied at will in order to increase or decrease the pressure between the pickup roller 4I and the applicator roller disc.

It is also to be observed that the applicator roller 43 by reason of its drive connections is driven in a direction opposite to the drive of a plate of glass upon the conveyor system. This opposed travel assures that a small bank or bubble X of aquadag suspension will be maintained upon the lower surface of a plate of glass which is being striped. The bubble, because of its pendent position, does not tend to spread or smear outwardly. This featureadds substantially in the application of striping of uniform width andthickness.

In order to maintain uniform contact of the applicator roller 43 with a plate of glass G passing thereover, spring pressed mechanism for the housing 45 is provided. Ihis mechanism includes a cross bar 56 interconnecting end elements 46 and being provided with a rod 51 appropriately threaded thereinto. The rod, it is tovbe observed, is also provided with a nut 58 engaging the cross bar positively tolock the Ybolt in position and aA cross bar 59 interconnecting the. rails 9 is provided with an opening 6I through which the rod 51 extends. The housing elements 45 are urged away from the bar 58 and also away from the glass plates traveling over the conveyor system by means of a helicalspring 62 coiled about the rod and engaging at opposite extremities respectively with the bar 56 and bar 59. To counteract spring 62, the outer end of rod 51 is also provided with a helical tension spring 63 which is appropriately secured to the rear extremity of a rod or bolt 64 which is secured by -means of locking nuts 466, in a bracket 61 upon the' contiguous rail 9.

Adjustment of the bolts or rods 51 and 64 permits the counterbalancing of the tension onsprings 62 and 64 to attain any desired degree of pressure on glass platesr G by striping roller 43. Moreover, the pressure is very uniform regardless of irregularities in the glass.

Suitable mechanism for holding a, plate of glass securely upon the conveyor .system while it is being striped by a Aroller 43, includes hold-down rollers 68, appropriately journaled in bearings 69 upQn-ianyfcqnyenient siilliortingdevicesuch as a; platform carried upon the rails 9;.L These; holdf.. dow-n-t rpllers; are'` disposed inpairs; uponA opposite sides of; the; applicator; or striping.rpl1ers4 3 ap,-4 proximatelyj in; vertical; alignment; with: twoA contiguous` conveyorsrollers.; one o f said conveyorv rollers;` of course being, roller I'Ib,` carrying the; driving connection for the pickup rollerdIf., Rolla' ers 68 are provided with discs 'I2 preferably,V of rubber or other material.y having; considerable, de#- gree; of resiliency,-v andalso; adapted to engage.` relatively rmlyrwith the. edgeportionszof asplatef.v ofjglassupon the conveyorfsystem'.

For; purposes, of" providing; a drive fonthe holds downvv rollers, one.; of them is= also; provided as showninFigs. 3 fand 5.. with -azfrictional drive discv 'I 4fhavingffrictionalcontact with. agcorresponding.v

disc 1.6 upon the. extremitypof. shaft. .I b1 opposite tofthe..sprocketigeanlm.. Shaftss arealso provided.: with sprocket. gears. orl V beltV pulleys VIV about which is trained` a suitable flexible drive'` connectionv '18; such as. a.v sprocket chain or. V beltin orderJ to drive both shafts synchronously.

It Willbe understood that the striping mechanisxrrV 34 applies stripes 0f aquadag alongEv 'two oppositeY edges of the plate of gIaSsG. Such stripes areiindicated at 'I9 inFig. 6a ofthe drawing; In order to stripe the plates-along edges indicated at8| in theA samegure, the plate is' rotatedthrough an angle 0190" andthen passed through the;l striping mechanism 35. For. purposes of effecting this rotation of theplates, suit.- able.; indexing mechanism is provided as shown in Figs.; 24a-nd 3. The glass after. it passes through stripingpmechanism` 34 and'` preparatory to being indexedis supported by its edge portions upon frustoeonical discs. (i3d) corresponding to discs ISLpreviously described which discs ISaare fixed upon stub` shafts; 82. havingfappropriate bearings 83,A upon,the-siderails;y If the platesto be striped,arerectangularrather than square, it will be manifest thatithezdiscs |30;A will not function whenV theglass; isirotatedto present the narrow side longitudinally of; the conveyor. To accommodate for such contingency cylindrical discs 4 (preferablyfknurled)` are provided onshats 82. Verticalrollersi.uponbrackets 85uv are also pro-V videdtol assist inguiding the plates. Discs 84" receivegand carry the glass/.if it is too; narrow-to.: rest ondiscsIla.

It willl beapparent; that the.,l stub` shafts are.- furthergprovidedpwith sprocket gears' 82a which, upononenside; of the mechanism are driven by: thephain 5 in synchronism with Ithe shafts In-` ordento Aprox/idea-v` driving connectionl for the stub` shafts upon; the .opposite side;of the system. a -shaft I|co,f theconveyor system is provided upon theextremity opposite to the sprocket-chainV I 5 with asprocket gear' about which is trained a sprocket chain 81 furthertrained about sprocket gearsi of the stub shafts 82.. By means of'these driving` connectionsl all yof the, stub shafts are drivenin ,synchronismg and are further synchro?. nized; with the remaining:conveyorfrollersf of.' the 1 system.

Betweenthe ends of vshaftsv 82- is disposed suit.- ablemechanisml for lifting plates of glass from thediscsiSa and for-indexing them through the desired angle. This mechanism includes a platform lahaving-,pads of rubber or other friction material'indicated at .89 secured thereuponfor purposes of engaging the lower surface of'aplatev ofvglass to be indexed. The platform is also/sup,- ported uponv a; vertical j shaft 9 I t having a: piston; (no t'fshowm.uponits:lcsveneictrernity.reciprocateu f present specification;

an` appropriateinlet Y 94', controlled byy an` electrif,1 M

cally;- actuated' valve.- 96 having. conductors96a."u which; will be described irranotherpcrtipngoffthe.- Gravtyimaybe.- relied, upon,toreturntheshaft after pressure-istreleased. inzcylinder'SZz.,

Forl purposes'- of rotating. the colummorfshaft:

9|A and, platform 88 afterf-they.- have been:v elev vated to lift a plate'aofgglasszgfrom:thegdiscs laag.,

a.. suitablef Geneva movement is provided. which, inthis.:` case-- includes a; disci. 9.11,; keyedgupomthe: shaftzand havingy slots? 98; forinedat;approprie-A ate. angular` intervals. The; drive; mecha'nisinafor.-n

3f thisr'dise;l includesv a; vertically;y disposed shaftg.-

rotatably mounted in a bearing; luluponxa supr-.f port |02; This: shaft, at its upperextremity: cart--l riesra horizontal arm; I '03, ,rigidly:lxed thereupon and have at its outerv extremity" a downwardlyj projecting pin |04, adapted to engage;` the v'slots 98, when: the shaftl 9| is aclfluateda.upwardlyftov raise theplatform 8,3. Thispinmayfbe mounted; to permitvertical; sliding in; itssocket in arm |03,.thus obviatingthepossibility ofgdamage to, thegmechanism. should theshaft B I A accidentallw` be s elevated', while the; arm; I 03. is; overf disc 9].

Thefpin will then merely; rise andride over: thei top of.; the-disc, but will dropdown to; operative;

position: after, the; arm has: rotated; sufficientlyrn 'fari Shaft; 99 isV further; provided at itsilower.: exi-:f tremitywithl a: bevel-gear I ,06 engaging;` a; cora responding, gear lil'! upon` a: transversely ex;-`

tended` shaft |08. Shaft |08 at; its outer` exs;VK .tremity,` is journaled in an appropriate bearingg I 09 andis also providedV with4 a sprocket;geary IIO, which is engaged by the lowerreachzofcthe-.fr

sprocket chain 81 driving stub shafts 82.

Forpurposes of; preventing over-running; of..V

the platform 88 after it has been indexedbyfthe pin I04`engagingslots 98,r a suitable detentde-.f

viceisprovided. This device includesa ballele-ik ment III engaging depressions-,H2- formedat angular intervals of190 in A.thelower 4'f aceof.the platform the; ball,beingcarriedupon the uppen extremity o f a supportingrod H37. The-roden? tends,- downwardly into a` casing I I4 containing;` ahelical springV llfadapted to act/date the-ironic upwardly in order to vmaintain i continuous; conf.. tact between the ball; I I I and: theindexing.plate form..

v Fornurposesfinitiating upwardI morementoff.' theplatform 88 when a plateofglass-is il1;..p,osig.

tion thereabove suitableflimit sw tches-.are'pro--v f vided.V These includeswitch, I I6 and astepping relay I I Bb, the llatterof which. is providedwith a connnection to thevalve mechanism 96finorder.;`

toprovide for,upwardactuatinof the' piston 9|,Y The glass plater strikingftheY limit, switch.` I I;

actuatesthe relay II Sbtoopenthevalve 96' thuslf elevating platform 88; When the` platform is" lowered, again permittingthe'glass tostrike'the switch I I6 the' stepping," relay will" operate i to.

neutralize or open ther circuit of 'the vaive; ,thus

preventingthefvalve from `opening'until the glassf has cleared-r the'- platform: They ste'eppdng'Vrelayv willl have then advanced to-closey the f circuitv preparatory forithe sequence involved -in lthe in' dexing-oflthefnextpl-ates Inasrrmch'astlie'*switch'-v platform 9a.

paratus that can be purchased by catalogue or over the counter of dealers, it is not deemed necessary to describe the details or circuits thereof.

Mechanism to operateV valve 96 to release the pressure in cylinder 32 includes a limit switch ||1 in the electrical circuit of the valve and disposed to be contacted by arms ||1a below the disc 91 when shaft 9| is in elevated position and is rotated by arm |03. There are four of the arms H'la so that during each indexing of the platform 88 the valve 96 is operated at the proper moment to return the platform to its lower position before the arm.|03 can make another circuit and again rotate the disc 91.

It will be apparent that if the washer W were fed and operated continuouslyy during the interval while the glass plates are being indexed, there would be a tendency for the plates from behind to pile up on the indexing mechanism. To obviate this tendency, a switch i|8 is provided in position to be engaged and operated by the platform 88 when the latter is lowered and to be released when the platform is raised. This switch is appropriately connected to stop the feeding of the Washer at the proper intervals. This -may be accomplished by connecting the switch in the circuit of motor and speed reducing mechanism '|c to stop the latter to produce the desired intervals in the line of glass plates.

It will be understood suspensions of conductive material such as graphite in water in the reservoir or troughs 42 of the striping'mechanism may tend to settle out upon appreciable periods of sanding. In order to prevent such settling, which would be detrimental to the uniformity of the coatings applied to plates of glass,k

suitable mechanism for circulating and'agitating the suspension is provided. This apparatus includes a tank or reservoir I I9, disposed upon the A Vertical shaft |2| within this reservoir carries agitator blades |22 designed to stir up the contents of the container. At its upper extremity the shaft |2| is provided with a V pulley or a sprocket gear |23 which is driven by a flexible connection such as a chain or Ibelt |24, further trained about a sprocket or pulley |26 upon the shaft 33.

The container ||9 is-prcvided with anoutlet conduit |2'| which as shown best in Fig. 3 leads toa pumping mechanism such as a conventional automobile fuel type pump |28 maintained upon the platform 9d. This pump is provided with an operating lever |29 actuated by a rotary cam |29a upon a shaft |291). This shaft is journaled in'bearings |290 and may be driven in any convenient manner, e. g. by a iiexible connection such as a belt |29d running on pulleys |29e and 129i on shafts |291) and 36.

Agconduit |30 connected to the pump, leads to a branched connection |3| having conduits |32, |33 and |34 branching therefrom. Conduits |32 and |33 supply the reservoir of the striping mechanism 34 while the connection |34 has branches |36 and |31 supplying the reservoir on opposite 'sides of the striping mechanism 35.

For purposes of returning suspended conductive material fromV the various reservoirs 42, a suitable system is provided. This includes branches |38 and |39 from the reservoirs of the striping mechanism 34 'discharging into a conduit |4|. u The reservoirs of the mechanism 35 also discharged into branch conduits |42 and |43 and discharging into line |44. Lines |4| and |44 in turn discharge into inlet conduit |46 leading to the reservoir ||9. Y

It will be apparent to those skilledv in the art that the forms of the invention described are typical. It will be apparent that numerous modications may be made therein without departure from the spirit of the invention or the scope of the appended claims.

I claim:

l. An apparatus for applying a stripe of electrically conductive nely divided solid material in aqueous suspension to a sheet of glass, said apparatus comprising a conveyor system for advancing the sheet of glass in a predetermined direction, stripe applying mechanism disposed below the plane of a sheet of glass upon the conveyor mechanism, said striping system comprising a reservoir for electrically conductive material, a shaft, a housing disposed upon the shaft, a driven pickup roller for electrically conductive material rigidly fixed upon the shaft dipping into said electro-conductive material in said reservoir, a striping roller having a shaft journaled in the housing and contacting with the pickup roller and being driven by the pickup roller in a direction to oppose the travel of a sheet of glass upon the conveyor, presser rollers engaging the top surface of said sheet of glass at points substantially spaced upon opposite sides from point of contact of the striping roller and means to drive the presser rollers in synchronism with the conveyor system.

2. An apparatus for uniformly striping a glass l sheet with an electrically conductive material in suspension, comprising a frame, a conveyor for moving the glass sheet forwardly in a substantially horizontal plane mounted in said frame, a shaft rotatably mounted in said frame, said shaft being positioned approximately right angularly with respect to the direction of movement of said glass sheet, a reservoir mounted on said frame below said shaft and through which a suspension of striping material is constantly circulated to maintain a uniform suspension, a driven suspension feed roller mounted onv said shaft and having its peripheral edge in contact with the suspension in said reservoir, a housing rotatably mounted on said shaft, said housing being vertically adjustable with respect to said shaft, a stub shaft rotatably mounted in said housing and extending horizontally therefrom parallel to said rst named shaft, a striping roller mounted on said stub shaft and having the peripheral edge thereof engaged with the peripheral edge of said feed roller to exert pressure thereupon, the pressure between said striping and feed rollers being variable in response to variations in the vertical adjustment of said housing to control the amount of suspension fed to said striping roller, said striping roller being driven by said feed roller in a direction opposite to the forward movement of said glass sheet, and resilient means connected to said frame and said housing for urging the striping roller supported by said housing into contact with said glass sheet.

3. An apparatus for applying uniform stripes of electrically conductive material to the faces of glass sheets moving through the apparatus, comprising a conveyor means for forward movement of the sheets inI a substantially horizontal plane, at least two striping mechanisms disposed in longitudinally spaced relation along and beneath said conveyor means, each stripe applying mechanism including a rotating stripe applying roller disposed in the path of movement of the glass sheets and means for maintaining uniform pressure of the roller in contact with the glass sheet, an indexing and elevating mechanism mounted beneath said conveyor means and disposed between the spaced stripe applying mechanisms in the path of movement of the glass sheets, said indexing and elevating mechanism' having a vertically reciprocable member for removing a glass sheet from the conveyor and rotating the sheet a predetermined number of degrees in the plane of movement of said sheet for striping by the next striping mechanism, control means associated with the indexing and elevating mechanism and conveyor means to stop forward movement of the glass sheet from the time the glass sheet moves into position above the vertically reciprocable member until the member REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTSY Number Name Date 896,751 Norton Aug. 25, 1908 1,568,605 Hough Jan. 5, 1926 1,857,769 Silberstein May 10. 1932 2,167,589 Schutz June 25. 1939 2,199,228 Obenshain Apr. 30, 1940 2,476,097 Kagen July 12, 1949 

